Philippine E-Journals

Adsorption Of Mercury By Rhizobium Loti Strain Bl1 80

Juanita C. Mamaril | Vilma T. Capuno | Lorele C. Trinidad | Estrella H. Lales

 

Abstract:

Rhizobium loti strain BL 1 80, an isolate from the roots of Leucaena leucocephala was observed to produce prodigious amounts of mucilaginous polysaccharides. This strain was cultured in varying concentrations of Hg2+ and found to survive even at high concentrations of 100 ppm Hg (10-4 M). After the cells of a 7-day old culture was removed, the concentration of Hg2+ in the supernatant was reduced to about 50% from the original concentration of 15 ppm Hg. The amount of Hg2+ reduced in the supernatant depends on the cell density, cell age, and time of agitation. Optimum growth parameters for mass culture of BLl 80 show a maximum cell count after 3- 4 days incubation period and maximum polysaccharide production after the 7th to 10th day of incubation. Mass cell growth is enhanced by increasing inoculum level from 2% to 4%. Transmission electron micrographs of LBl 80 cells grown in YEMB alone showed a thick outer cell layer. YEMB with Hg2+ showed the whole cell surface covered with a dense layer.